Watch how they talk to the cashier. That’s the preview of how they’ll talk to you later.

Behavior toward people who cannot affect somebody’s life is the most honest sample available, because nothing is being managed in those moments. Courtesy aimed at you early on may be effort; courtesy aimed at a stranger is character. Whatever you see there tends to arrive at your own door eventually.

Pay attention to those moments rather than to how you are being treated. Notice the tone with staff, with drivers, with anyone in a hurry. Watching costs you nothing and saves a great deal of surprise later.